Dungeon Boost

The original reward roll still happens normally. If the extra roll succeeds, the same pool is rolled again. This can give another item, a duplicate, or no copy of the item you want.

For a chest, the whole reward pool is rolled again; the game does not roll every item separately. For example, A Seal of Undead - Mergaheph can benefit because the complete Legendary Chest pool is rolled again.

Some bosses and dungeon objects give rewards directly instead of using a visible chest. Their eligible rewards receive the same extra roll. The affected chests and direct rewards are listed below.

Multi-reward chests that already perform several rolls are excluded. This includes the five named Treasure Chests in Eternal Chaos Arena, Dragon's Treasure Box in Labyrinth, and the Box in Veil. Lake in Dusk is also excluded because its direct boss loot—including A Seal of Phantasmal - Zigdris Faello—uses the normal monster-drop system.

Dungeon Boost is separate from the character Drop Rate and Box Drop Rate Increase stats. Those stats do not change the extra-roll percentages. For a rare item, Difficulty 3 is roughly 44% more likely and Difficulty 5 is nearly twice as likely, although the exact increase is slightly lower because both rolls can select the same item.

Exact chance for at least one copy: 1 − (1 − p)(1 − qp), where p is the item's chance in one roll and q is the extra-roll chance.